Publications and other reference materials referred to herein, including reference cited therein, are incorporated herein by reference in their entirety and are numerically referenced in the following text and respectively grouped in the appended Bibliography which immediately precedes the claims.
The number of transactions in the internet grows exponentially. The scalability of the internet is based on the distribution of tasks among the participants. Specifically, peer to peer, machine to machine, clients and servers execute independent transactions with no central controlling entity. A Certificate Authority (CA) is a prominent example of the opposite approach; a centralized entity that is heavily used as part of public key infrastructures or as part of the communication protocol to secure the transactions/communication in the internet. A user wishing to anonymously place a talkback in a website that operates under the present CA infrastructure, can not be revoked of his/hers anonymity, since the moderator of the website has no judgment whether to reveal the identity of the user or not. In extreme cases the website may appeal to a real judge and get a court order to reveal the IP address of the user, however if the user used anonymous surfing or was in a public place (e.g. internet cafe) then it will be impossible to reveal their identity.
Some ideas for anonymous systems that appear in the prior art are revocable privacy, anonymous credential systems, digital money and blacklisting. Hoepman [11] defines revocable privacy as designing systems in such a way that no personal information is available unless a user violates the pre established terms of service. Only in that case, his personal details (and when and how he violated the terms) are revealed to certain authorized parties. Stadler [14] defines cryptographic primitives for revocable privacy as fair blind signatures and publicly verifiable secret sharing. Later works use these primitives to achieve revocable privacy. The revocation mechanism of revocable privacy systems (e.g. [5, 12]) is initiated by a law enforcement entity and requires a central “judge” to decide whether the privacy should be revoked or not. Franklin [9] proposes the use of a single semi-trusted entity in a fair exchange environment, the third party is assumed not to collude with either of the other (client and server) parties. Moreover, if both parties are honest then they both learn each other's document. Users in anonymous credential systems (e.g. [4]) communicate anonymously with different servers in an unlinkable fashion. The CA (or open authority as it is called in those systems) issues the credentials to the users and the same entity may revoke the anonymity of the users. Another group of solutions is “k-times anonymous authentication” (k-TAA) systems [15]. As implied by their name, these systems provide anonymous authentication k times. Until the kth time, no one (not even the trusted party) can identify the user, whereas in the k+1 attempt, the anonymity of the user is revoked. The trusted party is involved only in the registration stage, hence, the server can revoke user anonymity by itself. Camenisch [3] extend k-TAA to allow k anonymous authentications in a single time period. Namely, after a predefined period of time, the counter is set to zero, and k is recounted. Other systems (e.g. [2, 16, 17, 18]) use blacklists in order to prevent the user from receiving service, whereas the anonymity of a misbehaving user is not revoked. Au [1] extends these works by adding reputation scores to anonymous users.
Methods for improving the deficiencies of the prior art have been presented, by the inventors of the present application, in [7].
It is a purpose of the present invention to provide a method for anonymous user to user network interactions.
It is an additional purpose of the present invention to provide a method for resolving disputes between users in network communications.
It is a further purpose of the present invention to provide a method for secure user to user network transactions.
Further purposes and advantages of this invention will appear as the description proceeds.